Medical science advances constantly and health care is an issue most people deem seriously. These days many simple medical measurement instruments such as thermometers, blood pressure meters, fat detection meters and the like are available for people to use themselves. For people to accurately know their own health conditions, aside from knowing how to correctly use the medical measurement instruments, they also have to understand how to correctly judge the measured outcome. The conventional medical measurement instruments, such as R.O.C. patent No. M284356, entitled “Blood pressure meter” indicates merely the measurement result by a digital value through a LCD device. The digital value alone does not inform users whether it is in the normal range. The digital value has to be used in cooperation with other measurement units (such as mmHg for measuring the blood pressure) to become meaningful. Hence to understand a person's physical condition the person has to know the correct measurement method and interpret the measured value. For people who do not have fundamental medical knowledge interpreting the measured value could be baffling, or mistaken interpretation could occur. After people have known how to interpret the measured digital value, they also have to know the normal range of the digital value to understand their physical conditions. People generally have a faster understanding and response to graphics and colors. Different colors give the brain different stimulations to allow people to generate different alerts (such as red color has the longest wavelength and is processed by the brain at a higher priority, thus gives people an alert sense). Hence the perception speed and degree of the brain on a measured digital value is slower and lower than color alteration and intensity variation of lighting lamps. Moreover, displaying merely the measured digital value does not generate instant alert to people who do not have sufficient medical knowledge or perception. Hence there is still room for improvement on the presentation method of the conventional medical measurement instruments in terms of enabling people of no medical knowledge or insufficient perception to quickly understand their physical conditions. This phenomenon of lacking graphic presentation also happens to the measurement of the physiological conditions of other living things (such as measuring the heart beat of cats). It also begs for improvement. R.O.C. patent No. M284890, entitled “Improved digital thermometer” discloses a technique which can generate two colors through a backlight panel to indicate a measured result. It indicates by mixing two colors of light in different ratio of light intensity. As people differ in their sensitivity and perception on colors, they have difficulty to differentiate the measurement variation by seeing the color mixed in varying ratios (such as to differentiate 60% of green light and 40% of red light). The interpretation result of different people could be different. Hence an improvement still is required to simplify the interpretation of measured result.